All you need is to copy the already-installed AmiKit folder (eg. C:\Program Files\AmiKit\) from your home PC to USB flash disk. Then you should be able to run AmiKit.exe launcher from USB. Or you can run WinUAE.exe (located in AmiKit\WinUAE folder), load the AmiKit config and run it if the launcher doesn't work.
The step by step guide can be found in this PDF document: Optimizing the AmiKit
Note that the document is almost a year old which means you don't need to install any cumulative updates. The current full AmiKit version available for download is v1.4.0
I would strongly recommend to convert AmiKit directory structure to a hardfile before you copy AmiKit to USB. This is because the directory files access is slow (especially on USB) while hardfile is MUCH faster with regards to Read/Write operations. Here's the guide
on how to do it.